The present invention relates to a drive for a male-mold-slide ejector slidably disposed in a slide of a mechanical metal-forming press, the drive having an angle lever, one leg of which acts upon the end of the ejector facing away from the male mold, and the other leg of which is in driving connection with a guide rod which is linked to a driving connecting rod for the slide and, in a timed manner, transmits driving movements to the angle lever.
A male-mold-side ejector can be a pin-shaped ejector penetrating the male mold. This is shown, for example in German Unexamined Patent Application DE-OS 28 27 561 A1. An ejector could also comprise at least one pin guided in parallel to the male mold and outside this male mold. An ejector can also comprise an ejector sleeve surrounding the male mold, for approximately sleeve-shaped workpieces or workpieces provided with a central recess, as in for example, German Patent 925 566 C3.
A drive for a male-mold-side ejector is known, for example, from German Examined Patent Application DE-AS 16 27 977 B2. The driving connection from the guide rod to the other leg of the angle lever is established by means of another angle lever which is pivoted in the frame of the press and to one leg to which the guide rod is linked. The other leg of this additional angle lever carries an actuating plate, against which the other leg of the angle lever actuating the ejector is held by a roller. The possible stroke of the slide, in this case, is limited by the length of the actuating plate against which the roller must continue to rest. A slide adjustment for an adaptation to different heights of the female mold and the male mold is neither provided in this case, nor can it be provided on account of the possible length of the actuating plate.
Another known drive for a male-mold-side ejector which is slidably disposed in a slide of a mechanical metal forming press and which has a lever that is pivoted in the slide, is known from German Patent 10 63 013 C3. Here, the lever has one arm and its extreme end acts upon the end of the ejector facing away from the male mold, while, in an area which is closer to the linking, a control 27.03.90 cam is formed on which a roller for actuating of the ejector rolls along which is disposed in a guide rod. The guide rod is linked to a driving connecting rod for the slide and is supported by a rocker linked to the guide rod and the slide. In this known drive, an adaptation to different heights of the female mold and the male mold is possible only to a very limited extent by means of a transversely adjustable wedge.
These two known drives have a common disadvantage in that the actuating force for a stripper is transmitted by way of a roller and a surface on which this roller rolls along. This results in only a linear contact which is not suitable for the transmission of higher stripper forces and during continuous operation is subjected to considerable wear.
Drives for female-mold-side ejectors are already known in crank-driven presses. See for example DE 23 39 404 A1 and DE 34 29 741 A1. In these drives, continuous link chains are provided as a driving connection from control connecting rods serving as the drive of the ejectors to actuating members acting directly on the ejectors. The actuating members are either ejector bars which are arranged in the frame of the press so that they can be moved in the moving direction of the slide, or they are ejector shafts which are pivoted in the frame of the press and carry the cams actuating the ejectors. However, these are female-mold-side ejectors for the drive of which a transmission of movements to angle levers disposed in the slide is not required.
It is therefore an object of the present invention to avoid an actuating surface - roller pairing with only a linear contact in the driving connection and to provide the driving connection such that a slide adjustment for an adaptation to different heights of the male mold and the female mold may be provided. Further, the adaptation to different heights should not impair the operation of the driving connection for the ejector.
This and other objects are provided by a drive for a male-mold-side ejector that is slidably disposed in a slide of a mechanical metal-forming press. This drive has a slide coupled to the ejector, a driving connecting rod coupled to the slide and driving the slide, and a guide rod having first and second ends and arranged at approximately a right angle to a moving direction of the slide. The drive has a two-armed lever having first and second arms and first and second ends, the first arm extending approximately parallel to the moving direction of the slide, the first end of the two-armed lever linked to the second end of the guide rod. A pin is fixed to the slide and is coupled to the two-armed lever such that the two-armed lever pivots on the pin. An angle lever is pivotably mounted in the slide, and has a first leg which acts upon an end of the ejector, and a second leg. A bracket is provided having first and second ends, with the first end of the bracket being coupled to the second end of the two-armed lever and the second end of the bracket being coupled to the second leg of the angle lever.
In the embodiments of the present invention, the driving connection between the connecting rod used for driving the slide and the angle lever used for driving the ejector, in each case, comprises a continuous link chain in which all connections may be constructed as closed joints. The two-armed lever which, at least with its arm facing away from the angle lever, is situated approximately in parallel to the moving direction of the slide, in the driving connection, bridges the area of the slide to which the driving connecting rod is linked and permits an adjustment of this linking in the slide. These types of adjustments do not impair the operation of the drive for the ejector because of the position of the guide rod approximately at a right angle with respect to the moving direction of the slide.
By adding another bracket in an embodiment of the invention, the link chain is advantageously lengthened to the connection with the ejector or a control pin acting upon this ejector.
By providing adjustability of the sliding pad carrying the pin in a circular-arc-shaped guide in the two-armed lever according to an embodiment of the invention, a changing of the transmission ratio is achieved between the excursion of the guide rod caused by the excursion of the driving connecting rod and the excursion of the angle lever, and thus the stroke of the ejector is changed.
In any case, the maximum of the stroke of the ejector during the return stroke of the slide occurs approximately at the position of the driving connecting rod which is achieved at 90 degrees crank angle after the lower/front dead center.
The present invention can be used in metal-forming presses with a vertical moving direction of the slide as well as in those with a horizontal moving direction of the slide, specifically in single-stage as well as in multi-stage metal-forming presses.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.